In some image forming apparatuses such as copiers, a phenomenon has occurred such that the surfaces of the sheets stacked on the paper output tray and lying next to each other have sometimes been adhered to each other by toner. Such a phenomenon is referred to as, for example, a sticking phenomenon. The phenomenon is considered to occur due to toner at a high temperature and in a molten state when the sheet having been subjected to fixing processing is outputted to the paper output tray without being sufficiently cooled down. In particular, the sticking phenomenon has easily occurred at a time of double-sided printing and high-speed printing and at a time of printing in which low melting point toner is used.
As one of means to prevent such a sticking phenomenon from occurring, a device can be designed so that a length of a conveyance path from a fixing device to the paper output tray may be extended. However, in a case where such a design is performed, the design may cause a problem that the device becomes larger in size.
Thus, some conventional techniques propose a technique in which a sheet that has passed through the fixing device is attempted to be cooled down by blowing air by using a cooling fan (refer to Patent Literature 1, for example).